Spicing Up The Battlemat: Water

After my previous post about improving D&D/Pathfinder battlefield environments went up, someone asked me via my twitter feed what combat would be like in water. The thought made me cringe. Water is a difficult environment for a number of reasons. Chief amongst them is that attempting to perform actions in water can slow the movement of a game down to a crawl. There's also the fact that it's much more difficult to represent three dimensional movement on a battlemat, and the fact that water tends to be pretty uniform and uninteresting as a combat environment.

Despite those factors which make water a headache, there are times when water combat is appropriate or even required. Players love to do things like sail ships, or explore sunken cities, and in a world like Pathfinder's, monsters lurk anywhere an adventurer might wish to go. So, with the hopes of making myself a better GM, I took some time today to consider water combat, and how it might affect gameplay. I divided the problem up into three sub categories: shallow water, deep water, and under water, each of which is detailed separately below. It also helps to be familiar with the swim skill (Pathfinder Core Rulebook page 108) and the water dangers section of the environment chapter (Pathfinder Core Rulebook page 445)

Keep in mind that these are primarily ideas for use on-the-fly by GMs. None of these are intended to be house ruled mechanics for water combat. Nor is are these lists intended to be a comprehensive gathering of everything which could happen to a character while fighting in or on water.

Shallow Water
A shallow water combat environment is defined as one in which the players are standing on their feet in some depth of water. Examples might include a stream or river, or near the shore of any larger body of water such as a lake or sea.

• Speed: In water up to a character's knees, speed should be reduced by 5. In water up to a character's waist or higher should reduce movement speed by half. Keep in mind that different size characters will deal with these issues at different depths of water.
  
• Strong Current: If there is a strong current present, the GM should be aware of it. Moving against the current could further reduce a character's speed by 5, while moving with it might increase a character's speed by 5. A character's speed in shallow water should never exceed their land speed unless they decide to start floating and allow the currents to propel them.
• Slippery Rocks: Underwater stones in shallow water make poor footholds. If a character is walking on slippery stones, moving at their full available speed, many standard actions such as attacking, or taking damage, should force them to make a reflex save (DC 10-12) or fall prone. Moving at half their available speed, or using a full round action to perform a standard action, gives a character enough time to find solid footing, which won't require any save.
• Stuck Foot: Any time a character makes a move action, there is a chance that the character's foot may become stuck. Either by becoming lodged between two rocks, or sucked down into a muddy riverbed. When this happens, a character may either use a move action to free it, or if he or she is willing to lose their shoe, a swift action. Determining where a foot can get stuck is best handled by the GM making secret notation of which spaces can potentially snag a character, and rolling a secret reflex save (DC: 8-12) for the character when they pass through those squares.
  
• Natural Caltrops: In a rocky area, or a fresh riverbed, there's always the possibility that the player may encounter stones which have not yet been eroded smooth. In some cases these stones may even be quite jagged, and act as natural caltrops (Pathfinder Core Rulebook Page 155) which "attack" at a -2 penalty. Placement of these sharp stones is best handled the same way that "foot sticking spots" are described above.
  
• Changing Depth: Keep in mind that depths change in all manner of water environments. Not only might there be sudden sink holes (which can be treated as pit traps which the character must make perception checks to be aware of), but even a gradual change in depth can be tactically significant in combat.
• Forced Drowning: Even in shallow water, drowning is a possibility. If attempting to drown a character in shallow water, the attacker must first grapple the victim and pin them. As when being "moved" into a hazardous location, pinning an opponent in these circumstances grants them a free attempt to break the grapple at a +4 bonus. Drowning is then handled as detailed in the Pathfinder Core Rulebook on page 445.
  

Deep Water
A deep water combat environment is defined as one which the characters cannot touch the bottom, and must swim in order to stay above the surface. Examples might include a pond, lake, or sea. It is important to note that shallow/deep water is more dependent on character height than on water depth. four or five foot deep water may still be considered shallow for a human, but for a gnome or halfling it would be considered deep.

• Concentrating On Swimming: Characters with less than 10 ranks in swim should lose their dexterity bonus to AC. Considering that a character in any significant armor would likely be unable to swim at all, any non-aquatic participants would likely have low AC due to this.
  
• Distracting Yourself: Taking a standard action, such as attacking, while in deep water should require a DC:12 swim check to stay afloat, or the character will go under water as described under the swim skill (Pathfinder Core Rulebook page 108) This assumes calm water. DCs should be adjusted for more difficult water.
  
• Forced Drowning: In deep water, attempting to drown an opponent requires less effort than in shallow water. A grapple check is still required, however rather than pinning the victim, the attacker need only "move" the victim down whilst pushing themselves up. As above, this entitles the victim to a free attempt to break the grapple at a +4 bonus.
  
• Slow Moving: Attack and damage rolls for characters swimming in deep water should receive a -4 penalty for light weapons, and a -8 penalty for larger weapons.
  
• Waves: When the water being fought in contains waves, they can easily interrupt combat. The combatants should be hit by waves every 2d4 rounds. When hit by the wave, characters are moved 1d4 spaces in a random direction along the wave's path. Characters are also Dazed for 1 round. A character who uses a move action can avoid becoming dazed.
  
• Currents: While currents are unlikely to move two combating characters apart, the characters will none the less be moved about by them. The longer the combat continues, the further away from their starting point they will be.
  
• Splashing Obstruction: If there is excessive action, the air around the characters may become filled with splashing water. In that case, both characters are granted concealment. (25% miss chance on a successful hit.)
  

Under Water
Under water combat is actually what the question which sparked this post was about. Underwater action is easily the most difficult kind. By necessity, being underwater for extended periods of time requires something which allows the characters to survive without oxygen; whether it's a potion they consumed, a primitive scuba suit, or even a unique kind of starfish which filters the air out of the water. For simplicity, I will assume that whatever mechanism allows the character to be underwater is unobtrusive.

• Deep Water: Concentrating on Swimming, Slow Moving, and Currents as described in the Deep Water section above would likely work the same way when under water.
  
• Three Dimensions: While this can be tricky to use on the mat, one of the biggest advantages to underwater combat. Foes can lie in ambush 100 yards above or below the PCs without being noticed, simply because the PCs aren't used to threats from above and below. In combat, height and depth can be more easily identified by placing pennies on the battle mat. A character 4 spaces above the ground would have 4 pennies next to their character's miniature on the battle mat. If the ground is significantly far away, define a baseline depth, and characters can use pennies for each space above that baseline, and dimes for each space below it.
  
• Loss of Breath: Whatever allows characters to breathe underwater is a target. If it's a Ring of Water Breathing it can be sundered. If there is a spell in place, it can be dispelled. Whatever the method in play, don't be afraid to force your players to prioritize breathing above defeating their foes.
  
• Blurry Vision: Most land-lubber eyes are not designed to see underwater. Unless goggles or some other method is being used, any attack made by a character whose species evolved on land should be subject to a 25% miss chance.
  

While using these, always remember that the point of role playing games is to have fun. If one of these mechanics is slowing down your battle and making everybody at the table bored, either don't use it, or find some other method to speed things along so the players can start having fun again.